Saturday, 14 April 2012

Interesting hybrid causes confusion for the unwary...

The following bird was seen at Rainton Meadows DWT in Durham yesterday (13th
April) and was put out as a Yellow-legged Gull, it was noticed however that the
bird didn't look quite right and had a few things wrong with it. The
Distribution of black on primaries is wrong for Lesser black-backed Gull and
would also be exceptional for pure Yellow-legged Gull. The upperparts tone
doesn't look right for Yellow-legged Gull and is more like that of a paler
Lesser black-backed Gull. The orbital ring is not as bright as should be for
Yellow-legged Gull and is closer to Lesser black-backed Gull. Therefore it was
concluded this bird is in fact a Herring x Lesser black-backed Gull hybrid.
Thanks to Mark Newsome for comments that were used in this blog post.

Pictures of bird HERE, also see an additional photograph of
the same bird below:

2 comments:

Cracking bird. What I think is weird is that you can tell just by looking at this bird that it isn't a Yellow-legged Gull. It's hard to explain but you can somehow see the LBBG influence. It's incredible how it looks (presumably with yellow-legs) like a Yellow-legged Gull but at the same time looks nothing like one! Am I right in thinking that the white tertial and secondary 'bar' on Yellow-legged Gull is generally not as broad or even as this as it tapers to the base of the wing?

The open wing shot on the link above gives a lot more detail on the primary pattern. P5 has small dark markings on the inner and outer webs, no way near close to a nice solid bar as in the vast majority of michahellis. The only shot with a fair bit of leg seems to show a washed out yellowish.I'm now wondering what a Herring x Yellow-legged Gull would look like. Would it be very similar to a LB-b x Herring hybrid, but presumably with some influence of mich. showing through (which this doesn't seem to have)? Well done to Dave Johnson and Derek C for getting the photos.